非饱和土的性状及膨胀土边坡稳定问题

为探究膨胀土物理力学性质指标对其膨胀变形影响。结合陕西安康地区某膨胀土工程实例，基于大量野外岩土勘察和室内测试数据资料，采用主成分分析法研究了膨胀土的膨胀变形与其物理力学性质指标间相关性及不同指标重要程度，建立了以主要物理力学指标为参数的膨胀土膨胀变形判别公式。影响膨胀土膨胀变形的物理力学指标可划分为反映外界环境的指标(含水率、饱和度、液性指数及含水比)、反映土体构造特征的指标(密度、干密度及孔隙比)、反映土体结构强度特征的指标(压缩系数和内摩擦角)及反映土体组成特征的指标(塑性指数和黏聚力)；含水率是影响膨胀土膨胀变形的关键指标，所建立判别公式可为类似地区膨胀土膨胀变形的判别提供参考。

Behavior of unsaturated soil and stability of expansive soil slope

This paper aims to explore the influence of physical and mechanical properties of expansive soil on swelling deformation. Based on principal component analysis(PCA),the paper studied the correlation between the swelling deformation of expansive soil and its physical and mechanical properties,and established the discrimination formula of swelling deformation with main physical indexes as parameters. It completed the above work through a large number of field geotechnical investigation and indoor test of an expansive soil project in Ankang,Shaanxi Province. The results show that the physical and mechanical indexes affecting the swelling deformation of expansive soil can be divided into the four types of factors. The first type of factors reflects the environment including water content,saturation,liquid index and water content ratio. The second type reflects soil structure characteristics including density,dry density and void ratio. The third reflects structural strength characteristics of soil mass including compressibility and internal friction angle. The fourth reflects soil composition including plasticity index and cohesion. Moisture content is the key index affecting the expansion deformation of expansive soil. The prediction model can provide a reference for the judgment of expansive deformation of expansive soil.